In my (very speculative) opinion the suit had more of a symbolic significance for Bryer. First of all, he bought it with one of his first paychecks when most 18 year olds would rather spend their paychecks on literally anything else, so you would think that means it would be important. And if the CBC interview of the alcohol checkpoint officer is accurate and it was the same suit, he a) took it to the Yukon in the first place when there aren't many formal events in the Yukon, and b) specifically transferred it from the first car to the second when they were most likely in a rush to grab belongings and set the first car on fire before being seen. What that symbolic significance was, or whether it can give any insight into the overall mindset of the pair at the time, is anyone's guess.
I looked at the video again and you're right, they do look to be similar height compared to that thing on the corner of the shelf. The other photo could have been older maybe.
As I said before, at this point I only see three options:
a) It was planned and they completely failed in almost every way imaginable at planning it properly (because if they planned it properly, they could have gotten away with it with nobody suspecting them, and not led the cops directly to them). Which means that, of course they probably wouldn't properly research the river conditions in the area either.
b) It was planned but intended to be a suicide mission from the start with various clues to keep LE trailing them until they ended it all in the wilderness and were never found, leaving a mystery for the ages of "did they really get away with it?" In that case potentially drowning in rapids would probably be an attractive possibility to them due to the low likelihood of their remains being found.
c) None of this was planned at all and they were freaking out in total "oh s***" mode the entire time and acting in a reactionary and impulsive way, fleeing to the most remote area they could think of with little to no research (how would they even research because as far as I've heard, they weren't even using cell phones at all after the murders) and that had predictable consequences. Looking back on their actions, I'm suspecting more and more that this is what actually happened.
Same. I also don't realistically see them being able to kill another person or steal another car in the Gillam area without it being discovered by now, considering the entire community is on high alert. Or to go two weeks on the roads without any confirmed sightings or CCTV footage (they have to stop for gas sometime). The only thing I can think of is maybe if they went through the woods all the way to the Moak Lake or Thompson area around where 280 is, and took a vehicle from there. But that seems highly improbable for a variety of reasons, not least of which is those communities are probably on the lookout for anything suspicious too.